Gelsemium elegans (G. elegans) is an extremely poisonous plant that is widely distributed in southern China and southeastern Asia. G. elegans poisoning events occur frequently in southern China, and are therefore an urgent public health problem requiring multidisciplinary action. However, the toxic components and toxicological mechanisms remain unclear. Here, we describe a systematic investigation on the toxic components of G. elegans, resulting in the isolation and identification of 120 alkaloids. Based on acute toxicity screening, the structure-toxicity relationship of Gelsemium alkaloids was proposed for the first time. Moreover, gelsedine- and humantenine-type alkaloids were detected in the clinical blood sample, and were confirmed to be causative in the poisoning. The most toxic compound, gelsenicine (1), had selective inhibitory effects toward ventral respiratory group (VRG) neurons in the medulla, which is the main brain region controlling respiration in the central nervous system. Gelsenicine (1) strongly inhibited the firing of action potentials in VRG neurons through its ability to stimulate GABA_A receptors, the main receptors involved in inhibitory neurotransmission. Application of GABA_A receptor antagonists successively reversed action potential firing in gelsenicine (1)-treated VRG neurons. Importantly, the GABA_A receptor antagonists securinine and flumazenil significantly increased the survival of poisoned animals. Our findings provide insight into the components and mechanisms of G. elegans toxicity, and should assist the development of effective emergency treatments for G. elegans poisoning.

Objective: To investigate the origin of infection and risk factors of a case with SARS-CoV-2 infection associated with overseas countries in the Ningbo-Zhoushan Port, Zhejiang Province, so as to provide the evidence for improving the COVID-19 control measures at ports. Methods: Ningbo Center for Disease Control and Prevention ( CDC ) and Beilun CDC conducted case finding and epidemiological surveys immediately after being informed. The general information, history of vaccination and the travel during the latest 14 days were collected from the positive case, and all close contacts were tracked. Saliva samples were collected for SARS-CoV-2 nucleic acid testing and whole-genome sequencing, and the sequencing results were aligned with the GISAID's EpiCoV database. The origin of infection and transmission route of the positive case was investigated. Results: A case was identified positive for SARS-CoV-2 nucleic acid during company M's routine screening in the Ningbo-Zhoushan Port on August 10, 2021, and was confirmed positive for SARS-CoV-2 nucleic acid by Beilun CDC and Ningbo CDC on August 11. Whole-genome sequencing showed SARS-CoV-2 B.1.617.2 ( Delta ) variant, which shared the highest homology with the virus sequence uploaded by Russia on June, 2021 ( Russia/MOW-RII-MH27356S/2021 ). The case was a bundling worker for overseas container ships, and reported communicated with foreign boatmen and contacted materials without protected interventions on the SINOKOR AKITA Container Ship between August 4 and 5, 2021. This ship anchored at Vladivostok, Russia from July 27 to 29, anchored at Ningbo Harbor on August 4, and departed on August 5. Then, 11 boatmen from this ship were tested positive for SARS-CoV-2 nucleic acid on August 8. One asymptomatic case was reported in this epidemic; 254 close contacts and 617 secondary close contacts were identified, and all were tested negative for SARS-CoV-2 nucleic acid. No new cases with SARS-CoV-2 infections were detected until August 25, 2021, and the emergency response was therefore terminated. Conclusions The infection was a sporadic COVID-19 epidemic associated with overseas countries, which was caused by Delta variant infection through contacts with foreign boatmen or materials by a bundling worker in Ningbo-Zhoushan Port; fortunately, no epidemic spread occurred. Intensified closed-loop management and increased frequency of SARS-CoV-2 nucleic acid test among high-risk populations, and improving the precision and rapid emergency treatment of COVID-19 epidemics are required for the containment of COVID-19 at ports.

Objective To investigate the role of BMP-2/Smad signaling pathway in the osteogenic differentiation of human aortic smooth muscle cells (HASMCs) caused by hyperphosphatemia -induced calcium phosphate (CaP) crystals.Methods High-phosphate medium was incubated at 37℃ for 3 days.CaP crystals and supernatant were isolated by ultracentrifugation.Scanning electron microscope and energy dispersive X-ray spectroscopy were performed for analysis of physicochemical characteristics of CaP crystals.HASMCs were cultured in vitro,and divided into high-phosphate,control,crystals and supernatant groups.Calcification was visualized by Alizarin red staining.Calcium loads in cells were quantified by o-cresolphthalein complexone method.Protein expression of bone morphogenetic protein-2 (BMP-2),Runt-related transcription factor 2 (RUNX2),osteopontin (OPN),phospho-Smad1/5/9 (p-Smad1/5/9) were quantified by Western blotting.After knockdowns of BMP-2 and Smad1 with small hairpin RNA (shRNA) interfering respectively in HASMCs,protein expressions were measured by Western blotting.Results High-phosphate medium induced the formation of CaP crystals.Compared with the cells in control group,CaP crystals significantly induced HASMCs calcification,increased calcium loads and up-regulated the levels of BMP-2,RUNX2 and OPN proteins (all P ＜ 0.05).After the addition of CaP crystals into HASMCs,the level of p-Smad 1/5/9 protein peaked at 30 min (P ＜ 0.05).After BMP-2 was knocked down in HASMCs,the expression of p-Smad1 caused by CaP crystals was blocked completely,and the expressions of RUNX2 and OPN caused by CaP crystals were reduced significantly (all P ＜ 0.05).After Smad1 was knocked down in HASMCs,the expressions of RUNX2 and OPN caused by CaP crystals were decreased significantly (all P ＜ 0.05).Conclusions Hyperphosphatemia-induced CaP crystals promoted osteogenic differentiation of HASMCs through the BMP-2/Smad signaling pathway.